John McDonough has never been known for charisma. He has always been the numbers guy.

White-haired and almost always in a dark suit, he talks of catastrophic budget cuts — layoffs of hundreds of employees or closings of several schools — in a slow steady voice that one might expect from an accountant or chemistry teacher still lecturing with a slide projector.

But in his 11 months as interim school superintendent in Boston, the 62-year-old career bureaucrat has dazzled legions of parents, educators, and civic leaders who view him as the mold for the city’s next permanent superintendent.

“He’s shaking things up,” said Michael Contompasis, a former Boston superintendent who is on the search committee for a new schools chief. “In his own quiet way, he is showing folks that there is a way to move the district forward, even though he will be in that role for a short period of time.’’

On Monday, McDonough received a vote of confidence when the superintendent search committee decided to extend its hunt well into the next school year, instead of sticking with its previous plans to announce finalists next month.

The delay is intended, in part, to give McDonough more time to execute changes in the system.

The favorable buzz for McDonough has raised an obvious question: Why not skip the search and keep him permanently?

‘I personally think we need somebody more of the caliber of John McDonough, who isn’t necessarily an educator first but is actually an administrator first.’

But McDonough, the system’s former chief financial officer, says he is willing to stay only until a permanent successor is found for Carol R. Johnson, who retired last summer.

In his office this month, McDonough reiterated that point, saying he found the accolades “very flattering” but “pretty awkward,” too.

“I’m extraordinarily humbled by it and I am overwhelmed by people’s expression of support and confidence in my leadership,” said McDonough, who makes $250,000 annually. “But I think five or 10 years [in this job] is beyond my scope.”

In his brief tenure, McDonough has stepped up efforts to intervene in struggling schools, given principals considerable autonomy to hire the teachers they want — over union objections — and warned more than 800 central office employees they may not have jobs after June as he overhauls the bureaucracy.

The experience of leading the school system, he said, has been “both incredibly rewarding and incredibly difficult.”

He likes “leading an organization of talented people committed to improving the lives of students in the city,” he said, but the 12- to 16-hour days can be exhausting.

“Time management is a problem. Adequate sleep is a problem,” he said. “Other than that, things are great.”

A career bureaucrat

In a city that has strongly preferred educators as superintendents, McDonough is a rare exception. For the past four decades, he has built a career mostly dealing with numbers inside School Department headquarters, an imposing granite structure in downtown Boston known for its ornate, towering columns.

He first reported there Nov. 6, 1973, as a temporary clerk in the administrative library, after recently earning a political science degree from Boston College.

From there, he moved to the payroll department where he served as an accountant, worked for one year as a budget coordinator in the mayor’s office of community development, and then returned to the School Department, ascending through the ranks to chief financial officer in 1996.

“My life has been in BPS,” said McDonough, who is not married and has no children. “There are actually very few things outside of BPS that are more important to me.”

McDonough, the second-oldest of nine children, grew up in Jamaica Plain and lived there until last June, when he moved to Charlestown. McDonough’s parents — Francis, a one-time lawyer for the National Labor Relations Board, and Eleanor, a former executive assistant for Governor Michael S. Dukakis — deeply believed in public service and social justice.

Unlike many Boston families who fled the city during the height of court-ordered desegregation in the 1970s, McDonough’s parents kept his younger siblings in the school system and became involved in the first school site councils.

Those values have influenced McDonough in his career. As chief financial officer, he developed a new way of allocating money that ensures schools with students who have the greatest educational challenges get more support, under a methodology known as “weighted student funding.”

Then, as interim superintendent, he launched an aggressive effort in January to recruit more teachers of color.

“He represents the best of public service,” said Michael O’Neill, the School Committee chairman.

Change maker

McDonough says his goal is to make the necessary changes so a new superintendent can have a smooth start, making him far more than just caretaker. It is a move that has won him many fans.

“If there is more to be done, he will figure out how to get it done,” said Samuel Tyler, who has known McDonough for more than 30 years and is president of the Boston Municipal Research Bureau, a government watchdog group. “He’s pretty determined.”

McDonough’s decades of institutional knowledge has been handy in pursuing his goal.

In November, he took advantage of an often-forgotten provision of the teachers-union contract that allows principals to hire teachers from the outside before depleting a pool of hundreds of internal candidates who have lost positions at other schools because of budget cuts, programmatic changes, or leaves of absences. The idea is to let principals choose the best possible candidate.

Observers say it was a gutsy move because the school system could wind up with dozens of extra teachers next school year without classrooms to report to. The teachers union has filed a grievance. McDonough says the school system will find other jobs for the teachers.

His inside knowledge has also aided him as he consolidates several divisions within School Department headquarters as he strives to make the bureaucracy more efficient and responsive.

Through it all, he has maintained good relations with the city’s often-combative teachers union. Richard Stutman, the union’s president, said any disagreements between the two have been “purely on policy issues” and “nothing personal.”

“He’s been transparent in all of his dealings with us,” Stutman said.

McDonough has won praise from Mayor Martin J. Walsh, who views him as a model for the next superintendent.

“I personally think we need somebody more of the caliber of John McDonough, who isn’t necessarily an educator first but is actually an administrator first,” the mayor said last month.

But McDonough’s tenure has had its bumps.

In October, he faced a bank of television cameras after bus drivers staged an apparent one-day strike, and parents criticized him for failing to warn them that the buses might not run that morning. A few weeks later, he unsuccessfully tried to avert a state takeover of two elementary schools with chronically low test scores, but the state pushed ahead.

And some school-based administrators say McDonough is not moving fast enough to eject higher-ranking staff members in the central office whom they consider to be ineffective.

“The feeling is John is a great person, but some of the people working for him should not be there,” said one administrator who was not authorized to speak and asked not to be identified. “When you have concerns, no one gets back to you, or when you do get in touch with someone, nothing gets done.”

Parents also have complained that the School Department remains unresponsive and that the best way to resolve problems is to contact McDonough directly.

Mary Lewis-Pierce, a parent, said she e-mailed McDonough one night about an ongoing issue and got a response back a half-hour later. She says she would like him to stay.

“He has a good handle on finances and is extremely responsive,” Lewis-Pierce said. “He can make changes in a non-inflammatory manner. You can’t ruffle that guy. I think a money manager is what BPS needs right now.”